The present invention relates to hybrid drive apparatuses.
There exists a “split hybrid drive apparatus” that is provided with two rotary electric machines and a planetary gear apparatus for power distribution. In relation to this, for example, U.S. Pat. No. 6,953,409 discloses a split hybrid drive apparatus H having the structure that is shown in FIG. 11. This hybrid drive apparatus H is provided with an input shaft I that is connected to an engine E, an output shaft O that is connected to wheels, a first rotary electric machine MG1, a second rotary electric machine MG2, three planetary gear mechanisms PG1 to PG3, and clutches C1 and C2 and brakes B1 and B2 that carry out the engagement between each of the rotating elements of the planetary gear mechanisms PG1 to PG3 or between the rotating elements and the case Ds. Here, for convenience, the three planetary gear mechanisms are, in order from the engine E side, the first planetary gear mechanism PG1, the second planetary gear mechanism PG2, and the third planetary gear mechanism PG3.
This hybrid drive apparatus H realizes a first split mode by engaging the first brake B1, and realizes a parallel mode from this state by engaging the first clutch C1 or the second clutch C2. In addition, this hybrid drive apparatus H realizes a second split mode by engaging the first clutch C1 and realizes the parallel mode from this state by engaging the second brake B2 or the second clutch C2. Thereby, this hybrid drive apparatus H is structured so as to enable the realization of two split modes and a parallel mode having a four-stage fixed gear change ratio. Here, in the split modes, the rotational drive power of the input shaft I (engine E), the first rotary electric machine MG1, and the second rotary electric machine MG2 is distributed and combined by the first planetary gear mechanism PG1 and the second planetary gear mechanism PG2, and is transferred to a shaft Ma, which rotates integrally with the second rotary electric machine MG2. In addition, the rotational drive power that has been transferred to this shaft Ma is transferred to the output shaft O via the third planetary gear apparatus PG3. In contrast, in the parallel mode, the rotational speed of the input shaft I (engine E) is varied at a prescribed gear change ratio and is transferred to the output shaft O. At this time, the first rotary electric machine MG1 and the second rotary electric machine MG2 rotate at speeds that depend on the vehicle speed and the gear change ratio, and act as a motor and a generator.
In addition, this hybrid drive apparatus H is not provided with a reverse shift speed in which the rotation of the input shaft I (engine E) is reversed and transferred to the Output shaft O. Therefore, in the reverse mode for carrying out reverse travel, this hybrid drive apparatus H is structured so as to transfer the reverse direction rotational drive power to the output shaft O via the third planetary gear mechanism PG3 by rotating the second rotary electric machine MG2 in the opposite direction.